Cleaning-in-place (CIP), which has replaced hand cleaning in, e.g., dairies, breweries and all potable liquid installations, involves circulating non-foaming or low foaming detergents through process equipment in the assembled state.
A typical basic CIP sequence may consist of the following five stages (for reference see "Hygiene for Management" by Richard A. Sprenger, 5th Ed., p. 135, published by Highfield Publications):
(1) pre-rinse with cold water to remove gross soil; PA0 (2) detergent circulation to remove residual adhering debris and scale; PA0 (3) intermediate rinse with cold water to remove all traces of detergent; PA0 (4) disinfectant circulation to destroy remaining microorganisms; PA0 (5) final rinse with cold water to remove all traces of disinfectants. PA0 In situ production of soap, emulsifiers, stabilizers due to the degradation of the soils. PA0 Easier to rinse away. PA0 Biodegradable waste products. PA0 Low foaming (especially an advantage in CIP, and particularly within membrane cleaning). PA0 Anticorrosive to metals and synthetic polymers used for membranes, sealings and tubes. PA0 The time for cleaning may be reduced. PA0 The energy consumption may be reduced. (The enzymatic cleaning is performed at a lower temperature). PA0 The cleaning may be more efficient. PA0 A possibility for phosphate free cleaning processes. PA0 The waste water treatment may be cheaper. PA0 The waste water may be used for feed or food. PA0 The waste water may also be used for other purposes like emulsifiers, buffers or cleaning agents for reuse or use in other places, such as lubrication purposes or polymer production. PA0 glycerol derivatives, PA0 sorbitan, glucose, sucrose derivatives, PA0 fatty acid ethoxylates, PA0 fatty acid ethoxylates propoxylates, PA0 fatty alcohol ethoxylates, PA0 alkyl phenol ethoxylates, PA0 fatty alcohol ethoxylates propoxylates, PA0 fatty esters of polyalcohol ethoxylates, PA0 end-blocked ethoxylates, PA0 polypropylene glycols, PA0 polyethylene glycols. PA0 alkylimidazoline, PA0 alkylbetaines, PA0 alkylamidobetaines, PA0 protein derivatives. PA0 I: Rinse with water--Enzymatic treatment--Rinse with water. PA0 II: Rinse with water--Enzymatic treatment--Rinse with water--Acid treatment--Rinse with water. PA0 III: Rinse with water--Acid treatment--Rinse with water--Enzymatic treatment--Rinse with water. PA0 IV: Enzymatic treatment--Acid treatment--optionally rinse with water. PA0 V: Acid treatment--Enzymatic treatment--optionally rinse with water. PA0 VI: Enzymatic treatment--Rinse with water--Acid treatment--optionally rinse with water. PA0 VII: Acid treatment--Rinse with water--Enzymatic treatment--optionally rinse with water.
The time allowed for each operation must be determined for each particular plant or circuit being cleaned.
The detergent in step (2) in the above mentioned sequence is often 0.5-1% NaOH/KOH (+/- surfactants) at 75-85.degree. C. followed by a rinsing with water followed by a treatment with 0.5-1% HNO.sub.3 (+/- surfactants) at 10-50.degree. C. The surfactants used are typically selected from nonionic and/or anionic surfactants often in combination with sequestering agents.
The industry wants more gentle cleaning media than the ones described above; a new cleaning media should offer one or more of the following advantages: Reduction of the water consumption, less damage to the equipment, lower temperatures, less risk for residues of surfactants and/or caustic and/or acids and/or sequestering agents in the food or beverage, less risk for accidents to the people handling the cleaning media. For membrane cleaning media also an improved cleaning efficacy is wanted.